Yes, you can apply as there are three ways to join PSUs as you can go through Gate exam, through direct recruitment and through their own entrances. So it is advisable to shortlist the PSUs in which you are interested and check their website to know about the beginning of application forms and also the officials publish advertisement of recruitment in newspaper as well so it would be better if you track the national newspaper on daily basis. Apart from that, if you want to go through Gate then below provided article will be helpful for you -

PSUs through Gate

Good Luck!!!